Voltage regulator system and method of use

ABSTRACT

Embodiments of the disclosure pertain to a voltage regulator system having a voltage regulation controller and a transformer assembly. The transformer assembly includes a coil winding, a multi-contact tap arrangement connected to the coil winding, and a multifurcated tap changer system that includes a first tap changer having a contactor element which makes contact with a first contact of the multi-contact tap arrangement when the controller provides a positioning stimulus based on sensing a voltage deviation from a nominal output voltage of the voltage regulator system. The multifurcated tap changer system further includes a second tap changer that is mechanically ganged to the first tap changer and includes another contactor element arranged to automatically make contact with a second contact of the multi-contact tap arrangement when the contactor element of the first tap changer makes contact with the first contact of the multi-contact tap arrangement.

FIELD OF THE DISCLOSURE

This disclosure relates to a voltage regulator system, and moreparticularly, to a voltage regulator system for power line substation,applications and method of use.

BACKGROUND OF THE DISCLOSURE

Power lines are often used to provide electric power to a large numberof consumers. Some of these consumers can be residential consumers whileothers are commercial consumers. Understandably, the amount of powerconsumed by these two types of consumers can vary during periods of theday as well as during seasons. For example, the amount of power consumedby commercial consumers during a workday can be higher than the amountof power consumed by commercial consumers during the night, whereas theamount of power consumed by residential consumers during the eveninghours in a residential area can be higher than the amount of powerconsumed during the workday. Utility companies typically accommodatesuch fluctuating power requirements by using various conventionaldevices. One among these various conventional devices, is a voltageregulator that provides for an increase in the voltage level on a powerline when the amount of current drawn through the power line rises, andvice-versa.

In some cases, the amount of current drawn through a power line over aperiod of time can exceed the current rating of a transformer coil orother elements of a conventional voltage regulator, thereby stressingand/or damaging various components of the voltage regulator. One ofthese components, which is known in the industry as a tap changer, isused to make contact at one of various tap points in a transformer coil.Excessive operations of the tap changer can not only lead to high wearand tear on the tap changer contacts but can also lead to arcing in somecases. Arcing is undesirable for many reasons, particularly becausearcing can be hazardous and can lead to equipment damage, reduction inthe lifespan of the equipment, and in some cases catastrophic failure.

BRIEF DESCRIPTION OF THE DISCLOSURE

Embodiments of the disclosure relate to a voltage regulator system, andmore particularly, to a voltage regulator system for power linesubstation, feeder, and industrial (i.e. oil and gas, industrial, wind,irrigation, mining, solar, etc.) applications and methods of use.Certain embodiments of the disclosure can provide a technical effectand/or solution directed to a voltage regulator system that can includea transformer assembly having two or more series windings coupled inparallel with each other, each winding having multiple taps. Theparallel coupling of the two or more series windings automaticallysplits a power line load current among the two or more series windings,thereby burdening each series winding with only a portion of the powerline load current. The transformer assembly also has two or more tapchanger assemblies that cooperate to allow for simultaneous activationof two or more movable contactor elements that are ganged together. Thereduction in current flow through each series winding as a result of theparallel coupling of the series windings, reduces or eliminates theamount of arcing that can occur when the movable contactor elements areactivated, thereby, in certain instances, extending the operational lifeof the voltage regulator system and providing various other benefits.

Certain other embodiments of the disclosure can provide a technicaleffect and/or solution directed to a voltage regulator system that caninclude a voltage regulation controller and a transformer assembly. Thetransformer assembly can include a coil winding, a multi-contact taparrangement connected to the coil winding, and a multifurcated tapchanger system that includes a first tap changer having a contactorelement which makes contact with a first contact of the multi-contacttap arrangement when the voltage regulation controller provides apositioning stimulus based on sensing a voltage deviation from a nominaloutput voltage of the voltage regulator system. The multifurcated tapchanger system further includes a second tap changer that ismechanically ganged to the first tap changer and includes anothercontactor element arranged to automatically make contact with a secondcontact of the multi-contact tap arrangement when the contactor elementof the first tap changer makes contact with the first contact of themulti-contact tap arrangement

According to one exemplary embodiment of the disclosure, a voltageregulator system includes a transformer assembly and a voltageregulation controller having a voltage sensing element. The transformerassembly, which is coupled to the voltage regulation controller, caninclude a coil winding, a first multi-contact tap arrangement, and amultifurcated tap changer system. The first multi-contact taparrangement, which is connected to the coil winding, includes a firstset of contacts. The multifurcated tap changer system includes a firsttap changer and a second tap changer. The first tap changer has a firstcontactor element that makes contact with a first contact in the firstset of contacts when the voltage regulation controller provides to thetransformer assembly, a first positioning stimulus that is based atleast in part on the voltage sensing element sensing a first voltagedeviation from a nominal output voltage of the voltage regulator system.The second tap changer is mechanically ganged to the first tap changer,and has a second contactor element that is arranged to automaticallymake contact with a second contact in the first set of contacts when thefirst contactor element makes contact with the first contact in thefirst set of contacts.

According to another exemplary embodiment of the disclosure, a method ofregulating voltage using a voltage regulator system includes providing avoltage regulation controller and a transformer assembly coupled to thevoltage regulation controller. The voltage regulation controllerincludes a voltage sensing element. The transformer assembly includes acoil winding, a first multi-contact tap arrangement, and a multifurcatedtap changer system. The first multi-contact tap arrangement, which isconnected to the coil winding, has a first set of contacts. Themultifurcated tap changer system includes a first tap changer having afirst contactor element and a second tap changer that is mechanicallyganged to the first tap changer, the second tap changer having a secondcontactor element. The method further includes sensing a first voltagedeviation from a nominal output voltage of the voltage regulator system,and in response to sensing the first voltage deviation, placing thefirst contactor element in contact with a first contact in the first setof contacts, the second contactor element automatically making contactwith a second contact in the first set of contacts.

According to yet another exemplary embodiment of the disclosure, avoltage regulator system includes a transformer assembly. Thetransformer assembly includes a coil winding, a first multi-contact taparrangement, a second multi-contact tap arrangement, a first tapchanger, a second tap changer, and a reversing switch. The firstmulti-contact tap arrangement, which is connected to the coil winding,has a first set of contacts. The second multi-contact tap arrangement,which is also connected to the coil winding, has a second set ofcontacts. The first tap changer includes a first contactor elementconfigured to make contact with a first contact of the first set ofcontacts over a first period of time and a first contact of the secondset of contacts over a second period of time. The second tap changerincludes a second contactor element that is mechanically ganged to thefirst contactor element of the first tap changer, the second contactorelement arranged to automatically make contact with a second contact ofthe first set of contacts over the first period of time and a secondcontact of the second set of contacts over the second period of time.The reversing switch, which is also connected to the coil winding, isoperative to electrically couple one of a first end or a second end ofthe coil winding to an output terminal of the voltage regulator system.

Other embodiments and aspects of the disclosure will become apparentfrom the following description taken in conjunction with the followingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described the disclosure in general terms, reference willnow be made to the accompanying drawings, which are not necessarilydrawn to scale, wherein like numbers refer to like elements throughout.

FIG. 1 illustrates an exemplary voltage regulator system in accordancewith one exemplary embodiment of the disclosure.

FIG. 2 illustrates a first exemplary implementation of the voltageregulator system shown in FIG. 1.

FIG. 3 illustrates some elements of an exemplary transformer assembly,the elements indicated in a symbolic format, in accordance with oneexemplary embodiment of the disclosure.

FIG. 4 illustrates an exemplary mechanical arrangement for operating thetransformer assembly shown in FIG. 1.

FIG. 5 illustrates an exemplary voltage regulator system having a singlecoil winding and a single tap changer that is susceptible to damageduring operation, in accordance with one exemplary embodiment of thedisclosure.

FIG. 6 illustrates a voltage regulator system having a single coilwinding and a multifurcated tap changer in accordance with an exemplaryembodiment of the disclosure.

FIG. 7 illustrates an exemplary mechanical arrangement for operating thetransformer assembly shown in FIG. 6.

DETAILED DESCRIPTION OF THE DISCLOSURE

The disclosure will be described more fully hereinafter with referenceto the accompanying drawings, in which exemplary embodiments of thedisclosure are shown. This disclosure may, however, be embodied in manydifferent forms and should not be construed as limited to the exemplaryembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will satisfy applicable legal requirements. Moreparticularly, the word “exemplary” as used herein indicates one amongseveral examples, and it should be understood that no undue emphasis orpreference is being directed to the particular example being described.Furthermore, the word “example” as used herein is intended to benon-exclusionary and non-limiting in nature

It should also be understood that certain words and terms are usedherein solely for convenience and such words and terms should beinterpreted as referring to various objects and actions that aregenerally understood in various forms and equivalencies by persons ofordinary skill in the art. Thus, words such as “contactor,” “contacts,”“taps,” “tap changers,” “winding,” and “coil” as used herein should beunderstood to refer to various elements that can be implemented in avariety of ways. More generally, a tap refers to one of multiplecontacts provided on a winding, and a tap changer can include a movablecontactor element like a wiper or a slider that can be moved in order toprovide contact with any selected one of the multiple taps. The movablecontactor element can be moved using a positioning stimulus provided bya voltage regulation controller in accordance with one or moreembodiments of the disclosure.

Attention is now drawn to FIG. 1, which illustrates an exemplary voltageregulator system 100 in accordance with one exemplary embodiment of thedisclosure. The voltage regulator system 100 has a pair of inputterminals 101 and 102 that can be used to couple a voltage source 105into the voltage regulator system 100. The voltage source 105 can be oneor more components associated with a power plant, such as a powertransformer that is coupled to a power generator (a gas turbine powerplant, for example) or an alternating current (AC) generator. Thevoltage regulator system 100 also has a pair of output terminals 103 and104 that can be used to couple the voltage regulator system 100 to aload 120.

The load 120 symbolically represents power-consuming components coupledto the voltage regulator system 100. The power consuming components canbe associated with various power consumers such as residential consumersand commercial consumers. A few examples of power-consuming componentsassociated with residential consumers can include lighting elements,heating elements, cooling elements, and domestic appliances, while a fewexamples of power-consuming components associated with commercial andindustrial consumers can include computers, motors, machinery, andoffice equipment.

An increase in power consumption by the load 120 can be characterized byan increase in an amount of current drawn from the voltage source 105and through the voltage regulator system 100. The voltage regulatorsystem 100 can include a transformer assembly 110 and a voltageregulation controller 115. The voltage regulation controller 115 has avoltage sensing element 117 configured to sense an amplitude of theoutput voltage present across the output terminals 103 and 104 of thevoltage regulator system 100 and a driver 116 that is coupled to thevoltage sensing element 117. The driver 116 delivers a positioningstimulus to the transformer assembly 110 under control of the voltagesensing element 117.

The voltage regulation controller 115 can be implemented in variousways. In a first exemplary implementation, the voltage sensing element117 can be a step-down transformer with a primary coil of the step-downtransformer connected to the output terminals 103 and 104 and asecondary coil that coupled to the driver 116. In this implementation,the driver 116 can provide to the transformer assembly 110, apositioning stimulus in the form of an electrical signal that is carriedover a coupling link 111 (a wire, for example) and coupled into asuitable tap changer element in the transformer assembly 110.

In a second exemplary implementation that is described below in moredetail, the voltage regulation controller 115 can be implemented in theform of a synchronous electric motor. A winding of the synchronouselectric motor can operate as the voltage sensing element 117 and arotor shaft of the synchronous electric motor constitutes the driver116. The coupling link 111 in this second exemplary implementation is amechanical coupling system that transfers a positioning stimulus (arotary action of the rotor shaft) into two or more tap changerassemblies in the transformer assembly 110.

Irrespective of the manner in which the voltage regulation controller115 is implemented, the voltage regulator system 100 operates to provideoutput voltage regulation by compensating for any changes in outputvoltage that may occur due to changes in current drawn by the load 120.More particularly, when there is an increase in current drawn by theload 120, the voltage sensing element 117 in the voltage regulationcontroller 115 senses a drop in the output voltage across the outputterminals 103 and 104 of the voltage regulator system 100. The voltageregulation controller 115 then configures the transformer assembly 110to reduce a voltage drop in the series path of the current. Conversely,when there is a decrease in current drawn by the load 120, the voltagesensing element 117 in the voltage regulation controller 115 senses arise in the output voltage across the output terminals 103 and 104 ofthe voltage regulator system 100. The voltage regulation controller 115then configures the transformer assembly 110 to introduce a largervoltage drop in the series path of the current.

Thus, when an increased current draw by the load 120 leads to about a10% reduction (for example) in a nominal output voltage of 440V providedby the voltage regulator system 100, the voltage present across theoutput terminals 103 and 104 will be about 396V (440V−44V). The voltageregulation controller 115 responds by sensing the voltage drop andreducing the voltage drop across the transformer assembly 110 by asuitable amount in order to raise the voltage present across the outputterminals 103 and 104 back towards 440V.

On the other hand, when a change in the load 120 leads to about a 10%decrease (for example) in an amount of current drawn out of the voltageregulator system 100, the voltage present across the output terminals103 and 104 can rise by about 10% to 484V (440V+44V). The voltageregulation controller 115 responds by sensing the voltage rise andincreasing the voltage drop across the transformer assembly 110 by asuitable amount in order to adjust the voltage present across the outputterminals 103 and 104 back towards 440V.

As mentioned above, in the other exemplary implementation, the voltagesensing element 117 is a winding of a synchronous electric motor and arotor shaft of the synchronous electric motor is operative to providethe positioning stimulus to the transformer assembly 110 for moving atleast one contactor element of a tap changer from one tap to another forselectively increasing or decreasing the voltage drop in the transformerassembly 110.

FIG. 2 illustrates a few exemplary components that can be included inthe voltage regulation controller 115 and in the transformer assembly110 in accordance with an exemplary implementation of the voltageregulator system 100. In this exemplary implementation, the transformerassembly 110 is implemented in the form of a split-coil transformerassembly 200. The split-coil transformer assembly 200 not only addressescertain stress-related and/or damage-related issues due to high currentdraw by the load 120 but also addresses some arcing-related issuesduring tap changing operations. In this exemplary embodiment, thevoltage sensing element 117 in the voltage regulation controller 115 isa step-down transformer 250. The primary coil of the step-downtransformer is connected to the output terminals 103 and 104, which canbe at 440V for example. The step-down transformer action provides for alower voltage that is coupled into the driver 116. The driver 116, whichcan include a circuit board containing electronic components, can usethis lower voltage to generate a positioning stimulus in the form of anelectrical signal that is carried over the coupling link 111 into thesplit-coil transformer assembly 200.

In another example embodiment, as indicated above, the voltage sensingelement 117 can be a single winding of a synchronous electric motor. Inthis implementation, a rotor shaft of the synchronous electric motorsteps clockwise when the nominal output voltage at the output terminals103 and 104 changes in one direction (rises above the nominal voltage,for example) and steps counter-clockwise when the nominal output voltageat the output terminals 103 and 104 changes in an opposite direction(falls below the nominal voltage, for example). The rotor shaftcooperates with the driver 116 to move tap changers inside thesplit-coil transformer assembly 200 in order to vary the voltage dropprovided by the split-coil transformer assembly 200. Additional detailsof this exemplary implementation will be described below using anotherfigure.

Turning now to the split-coil transformer assembly 200, in thisexemplary embodiment, a pair of tap changers 240 and 245 aremechanically ganged to each other. In other exemplary embodiments, morethan two mechanically ganged tap changers can be used. The first tapchanger 240 includes a contactor element 205 (a wiper or a slidingcontactor, for example) that makes contact with a first coil winding215A. The contactor element 205 has one end connected to the inputterminal 101 and another end arranged to make contact under control of apositioning stimulus provided by the voltage regulation controller 115,with any one of several taps provided on the first coil winding 215A.The first coil winding 215A has a first end terminated on a positiveterminal and a second end terminated on a negative terminal. A firstreversing switch 225 is arranged to provide a selectable contact betweenone of the positive terminal or the negative terminal and to couple thefirst end or the second end of the coil winding 215A to the outputterminal 103 thereby allowing for reversal of winding sense.

The second tap changer 245 is substantially identical to the first tapchanger 240 (but can be different in other implementations). Thus, thesecond tap changer 245 similarly includes a contactor element 210 (awiper or a sliding contactor, for example) that makes contact with asecond coil winding 215B. The contactor element 210 has one endconnected to the input terminal 101 and another end arranged to makecontact with any one of several taps provided on the second coil winding215B, under control of the same positioning stimulus that is provided tothe other contactor element 205. The second coil winding 215B has afirst end terminated on a positive terminal and a second end terminatedon a negative terminal. The reversing switch 230 is arranged to providea selectable contact between one of the positive terminal or thenegative terminal and couple the first end or the second end of thesecond coil winding 215B to the output terminal 103 thereby allowing forreversal of winding sense of the second coil winding 215B. The reversingswitch 230 is mechanically ganged with the reversing switch 225.

As indicated above, the contactor element 205 and the contactor element210 are both coupled to the input terminal 101, and the reversing switch225 and the reversing switch 230 are both coupled to the output terminal103. This arrangement provides for a parallel combination of the firsttap changer 240 and the second tap changer 245, as well as for aparallel combination of the first coil winding 215A and the second coilwinding 215B.

FIG. 3 illustrates some elements of the split-coil transformer assembly200 in a symbolic format for purposes of specifically describing certainfeatures provided by the parallel combination of the first coil winding215A and the second coil winding 215B. If the split-coil transformerassembly 200 were to be implemented in the form of a single coil windingrather than in split-coil form, a load current (I_(load)) drawn by theload 120 will propagate in its entirety through the single coil winding.To elaborate upon this aspect, it can be assumed for purposes ofdescription that the split-coil transformer assembly 200 shown in FIG.2, is implemented by using only the tap changer 240 and the first coilwinding 215A (omitting the tap changer 245 and the second coil winding215B). As a result of this configuration, the load current through(I_(load)) flows only the first coil winding 215A, thereby necessitatingthat the first coil winding 215A have a power dissipation capability tohandle the entire load current (I_(load)). Furthermore, the single tapchanger 240 has to withstand a large amount of arcing when the contactorelement 205 is moved from one tap to another during voltage regulation.In some cases, the arcing can be severe enough to readily damage partsof the tap changer 240, while in other cases, a number of arcing eventsover a period of time can have a cumulative effect that reduces the meantime between failures (MTBF) of the tap changer 240.

Consequently, in accordance with the disclosure, one may use asplit-coil winding arrangement 300 containing “n” (n≥2) coil windingscoupled in parallel to each other. Thus, in the exemplary embodimentshown in FIG. 3, the coupling of the first coil winding 215A in parallelwith the second coil winding 215B accommodates a split in the loadcurrent, with each of the first coil winding 215A and the second coilwinding 215B propagating only a half amplitude of the load current.Understandably, the load current will be divided exactly in half onlywhen the first coil winding 215A is identical to the second coil winding215B. However, in some other exemplary embodiments, the first coilwinding 215A and the second coil winding 215B can be non-identical, andthe load current can be split proportionally between the first coilwinding 215A and the second coil winding 215B based on a difference inAC impedance presented by each of the first coil winding 215A and thesecond coil winding 215B.

The amplitude of the load current carried by each of the first coilwinding 215A and the second coil winding 215B can be further reduced insome exemplary implementations, by adding one or more additional coilwindings (shown in dashed line format) in parallel with the first coilwinding 215A and the second coil winding 215B. Thus, if four identicalcoil windings are provided in parallel with each other, the amount ofthe load current (I_(load)) flowing through each individual coil windingis equal to one-fourth of the load current provided to the load 120.Similarly, the use of “n” (n≥2) tap changers in place of a single tapchanger provides for load current sharing and reduction in arcing aswell as contact wear and tear.

The reduction in load current flowing through the use of “n” coilwindings and/or “n” tap changers in accordance with the disclosure notonly reduces a steady-state power dissipation in each of the “n” coilwindings and/or “n” tap changers (in comparison to a single coil windingand/or single tap changer) but can also provide for a significantreduction in arcing when the respective contactor elements areconcurrently moved from one tap to another during voltage regulation.This concurrent action of the multiple contactor elements will now bedescribed using the exemplary implementation shown in FIG. 4.

FIG. 4 illustrates an exemplary mechanical arrangement for concurrentlyoperating the contactor element 205 and the contactor element 210 of thesplit-coil transformer assembly 200 shown in FIG. 2. In this exemplarymechanical arrangement, the voltage regulation controller 115 includes asynchronous electric motor 420 coupled to the voltage sensing element117. The voltage sensing element 117 is a step-down transformer with aprimary coil connected to the output terminals 103 and 104 of thevoltage regulator system 100 and a secondary coil that provides power tooperate the synchronous electric motor 420. In this exemplaryimplementation, the coupling link 251 (shown in FIG. 2) is a mechanicalcoupling system 415 that transfers a positioning stimulus (a rotaryaction of a rotor shaft 404 of the synchronous electric motor 420) intoeach of the tap changer 240 and the tap changer 245. More particularly,the mechanical coupling system 415 transfers the positioning stimulusinto the tap changer 240 via a first shaft 416 and into the tap changer245 via a second shaft 418.

The first shaft 416 is inserted through a central opening in a circularelement 417 for holding and rotating the circular element 417, while thesecond shaft 418 is inserted through a central opening in a circularelement 419 for holding and rotating the circular element 419. Thecontactor element 205 is mounted on the circular element 417 and thecontactor element 210 is mounted on the circular element 419. In effect,the mechanical coupling system 415 provides a mechanical ganging of thecircular element 417 with the circular element 419, whereby a rotarymovement of the circular element 417 is automatically replicated by thecircular element 419. The mechanical ganging of the circular element 417with the circular element 419 in turn automatically provides for acoordinated mechanical ganging operation of the contactor element 205with respect to the contactor element 210. The mechanical couplingsystem 415 can include one or more of various components such as shafts,gears, pulleys, and belts, that can be used to couple the rotor shaft404 to the circular element 417 and the circular element 419 in themanner described above.

In one exemplary implementation, the synchronous electric motor 420rotates the rotor shaft 404 in a clockwise direction to a first angularposition when the output voltage changes in one direction (rises abovethe nominal voltage, for example) and rotates the rotor shaft 404 in acounter clockwise direction to a second angular position when the outputvoltage changes in an opposite direction (falls below the nominalvoltage, for example).

The contactor element 205, which can be implemented in various ways(such as in the form of a spring-finger or a spring-loaded pin), makescontact with one or more of multiple taps located on a circular taphousing 421 that is a part of the split-coil transformer assembly 200(shown in FIG. 2). More particularly, in this exemplary implementation,the contacting element 205 is arranged to make contact with a tap 401 onthe circular tap housing 421 under control of the synchronous electricmotor 420 when the output voltage across the load 120 is at a nominalvoltage, say 440V, for example. When the output voltage deviates by afirst amount below the nominal voltage, the positioning stimulusprovided by the rotor shaft 404 of the synchronous electric motor 420via the mechanical coupling system 415, to the first shaft 416 (acounter-clockwise rotation for example) makes the contacting element 205rotate away from the tap 401 and make contact with another tap 403 ofthe circular tap housing 421. When the output voltage deviates further,the positioning stimulus provided by the rotor shaft 404 of thesynchronous electric motor 420 to the first shaft 416 (acounter-clockwise rotation for example) makes the contacting element 205rotate away from the tap 403 to the next adjacent tap and so on.Similarly, when the output voltage deviates by a first amount above thenominal voltage, the positioning stimulus provided by the rotor shaft404 of the synchronous electric motor 420 mechanical coupling system415, to the first shaft 416 (a clockwise rotation, for example) makesthe contacting element 205 rotate away from the tap 401 and make contactwith another tap 402 of the circular tap housing 421.

As can be understood, the positioning stimulus provided by the rotorshaft 404 of the synchronous electric motor 420 mechanical couplingsystem 415, to the shaft 416 is concurrently provided to the secondshaft 418 as well. The rotation of the second shaft 418 causes thecontactor element 210 to rotate in synch with the contactor element 205and make contact with one or more of a number of taps on the circulartap housing 422 that is also a part of the of the split-coil transformerassembly 200 (shown in FIG. 2).

Furthermore, as described above with respect to FIG. 2, the amount ofcurrent carried by each of the first coil winding 215A and the secondcoil winding 215B as a result of the parallel coupling of the two coilwindings, is half as much would be carried by a single coil winding (ifonly a single coil winding was to be used). The reduction in current notonly provides for a significant reduction in arcing when the respectivecontactor elements are concurrently moved from one tap to another duringvoltage regulation, but also spatially distributes the arcing and theassociated heat emission to two separate locations. The two separatelocations correspond to the spacing between the first coil winding 215Aand the second coil winding 215B in the voltage regulator system 100.The reduction in arcing as well as distribution of heat emission over anextended area can extend the operational life of the voltage regulatorsystem 100 and providing various other benefits.

FIG. 5 illustrates an exemplary voltage regulator system 500 having asingle coil winding 515 and a single tap changer 510. The tap changer510 includes a contactor element 513 (a wiper or a sliding contactor,for example) that moves from making contact with a first tap 511 to asecond tap 512 of the single coil winding 515 when the tap changer 510is provided a positioning stimulus (not shown). As a result of thisarrangement, wherein the entire load current (I_(load)) propagatesthrough the contactor element 513 and one of the first tap 511 or thesecond tap 512, the tap contacting operation carried out via thecontactor element 513 can be accompanied by excessive arcing (andassociated heating) in some cases when the load current has a largeamplitude. Furthermore, there can be an undesirable amount of wear andtear on the tap contacts due to this large current flow.

FIG. 6 illustrates a voltage regulator system 600 in accordance withanother exemplary embodiment of the disclosure. The voltage regulatorsystem 600 includes a transformer assembly 650 coupled to the voltageregulation controller 115 in a manner similar to that described abovewith reference to FIG. 2 and other figures. The transformer assembly 650includes a single coil winding 625 and a multifurcated tap changersystem 605. The single coil winding 625, which incorporates a number ofmulti-contact tap arrangements, has a first end terminated on a positiveterminal and a second end terminated on a negative terminal. A reversingswitch 635 is arranged to provide a selectable contact between one ofthe positive terminal or the negative terminal and to couple the firstend or the second end of the single coil winding 625 to the outputterminal 103 thereby allowing for reversal of winding sense.

The multifurcated tap changer system 605 addresses at least some of theissues encountered by using the single tap changer 510 in the voltageregulator system 500 described above. In this exemplary embodiment, apair of tap changers 610 and 615 are mechanically ganged to each other.It should be understood that “n” (n≥2) such tap changers can be gangedtogether in accordance with one or more embodiments of the disclosure. Anumber of multi-contact tap arrangements (such as a first multi-contacttap arrangement 620 and a second multi-contact tap arrangement 630) areprovided on the single coil winding 625. The first tap changer 610includes a contactor element 611 (a wiper or a sliding contactor, forexample) that has a first end connected to the input terminal 101 and asecond end arranged to make contact with a first contact 621 among afirst set of contacts provided in the first multi-contact taparrangement 620, when a first positioning stimulus is provided to themultifurcated tap changer system 605 by the voltage regulationcontroller 115. The second end of the contactor element 611 is furtherarranged to make contact with a first contact 631 among a second set ofcontacts provided in the second multi-contact tap arrangement 630 when asecond positioning stimulus is provided to the multifurcated tap changersystem 605 by the voltage regulation controller 115.

The second tap changer 615 includes a contactor element 616 (a wiper ora sliding contactor, for example) that has a first end connected to theinput terminal 101 and a second end that is arranged to automaticallymake contact with a second contact 622 among the first set of contactsprovided in the first multi-contact tap arrangement 620, when the firstpositioning stimulus is provided to the multifurcated tap changer system605 by the voltage regulation controller 115. The contactor element 616is further arranged to make contact with a second contact 632 among thesecond set of contacts provided in the second multi-contact taparrangement 630 on the single coil winding 625 when the secondpositioning stimulus is provided to the multifurcated tap changer system605 by the voltage regulation controller 115.

As a result of the ganged operation and connectivity provided by thefirst tap changer 610 and the second tap changer 615, the load current(I_(load)) flowing through the multifurcated tap changer system 605 isautomatically divided into two parallel paths (“n” parallel paths when“n” tap change assemblies are coupled together) thereby addressing atleast some aspects associated with arcing and heat dissipation. Themulti-contact tap arrangements provided on the single coil winding 625further provides for lowered contact resistance and a reduction in anamount of arcing and heat generation when the load current has a largeamplitude.

FIG. 7 illustrates an exemplary mechanical arrangement for concurrentlyoperating the contactor element 611 and the contactor element 616 of thetransformer assembly 650 shown in FIG. 6. Some aspects of the operationof this mechanical arrangement can be understood in view of thedescription provided above with respect to the mechanical arrangementshown in FIG. 4. However, it will be pertinent to draw attention to awiring connection 705 provided between the contact 621 and the contact622, which constitutes a portion of the first multi-contact taparrangement 620. The wiring connection 710 provided between the contact631 and the contact 632 constitutes a portion of the secondmulti-contact tap arrangement 630.

Turning back to FIGS. 1-4 and the associated description, in oneexemplary implementation in accordance with an embodiment of thedisclosure, a voltage regulator system can include a voltage regulationcontroller and a split-coil transformer assembly. The voltage regulationcontroller can have a voltage sensing element. The split-coiltransformer assembly, which is coupled to the voltage regulationcontroller, can include a first coil winding, a first tap changer, asecond coil winding, and a second tap changer. The first coil windingcan include a first set of taps. The first tap changer can include afirst contactor element that makes contact with a first tap in the firstset of taps when the voltage regulation controller provides to thesplit-coil transformer assembly, a first positioning stimulus that isbased at least in part on the voltage sensing element sensing a firstvoltage deviation from a nominal output voltage of the voltage regulatorsystem. The second coil winding, which is electrically coupled inparallel with the first coil winding, can include a second set of taps.The second tap changer is mechanically ganged to the first tap changerand can include a second contactor element arranged to make contact witha first tap in the second set of taps when the first contactor elementmakes contact with the first tap in the first set of taps.

In certain aspects of the embodiment of the disclosure, the firstcontactor element of the voltage regulator system makes contact with asecond tap in the first set of taps when the voltage sensing elementsenses a second voltage deviation from the nominal output voltage, andthe second contactor element is further arranged to make contact with asecond tap in the second set of taps when the first contactor elementmakes contact with the second tap in the first set of taps.

In certain aspects of the embodiment of the disclosure, the voltagesensing element of the voltage regulator system can include a motor thatis electrically coupled to one or more output terminals of the voltageregulator system, the motor comprising a rotor shaft that rotates to afirst angular position when the motor senses the first voltage deviationfrom the nominal output voltage and rotates to a second angular positionwhen the motor senses the second voltage deviation from the nominaloutput voltage.

In certain aspects of the embodiment of the disclosure, each of thefirst tap changer and the second tap changer of the voltage regulatorsystem can include a circular plate having a central opening, that isprovided for insertion of the rotor shaft of the motor.

In certain aspects of the embodiment of the disclosure, the firstvoltage deviation from the nominal output voltage is a positivedeviation from the nominal output voltage and the second voltagedeviation from the nominal output voltage is a negative deviation fromthe nominal output voltage.

In certain aspects of the embodiment of the disclosure, each of thepositive deviation and the negative deviation is defined on a percentagebasis with respect to the nominal output voltage.

In certain aspects of the embodiment of the disclosure, the split-coiltransformer assembly can further include a first reversing switch and asecond reversing switch. The first reversing switch is connected to thefirst coil winding and is operative to electrically couple one of afirst end or a second end of the first coil winding to an outputterminal of the voltage regulator system. The second reversing switch,which is mechanically ganged with the first reversing switch, isconnected to the second coil winding, and operative to electricallycouple one of a first end or a second end of the second coil winding tothe output terminal of the voltage regulator system when the firstreversing switch electrically couples the one of a first end or thesecond end of the first coil winding to the output terminal of thevoltage regulator system.

In yet another embodiment of the disclosure, a method for regulatingvoltage can include providing a voltage regulator system having asplit-coil transformer assembly. The split-coil transformer assembly caninclude a first coil winding, a second coil winding, a first tapchanger, and a second tap changer. The first coil winding has a firstset of taps. The second coil winding, which is electrically coupled inparallel with the first coil winding, has a second set of taps. Thefirst tap changer can include a first contactor element. The second tapchanger can include a second contactor element that is mechanicallyganged to the first contactor element of the first tap changer. Themethod can also include sensing a first voltage deviation from a nominaloutput voltage of the voltage regulator system, and in response tosensing the first voltage deviation, activating the first contactorelement to make contact with a first tap in the first set of taps andthe second contactor element to make contact with a first tap in thesecond set of taps.

In certain aspects of the embodiment of the disclosure, the method caninclude sensing a second voltage deviation from the nominal outputvoltage of the voltage regulator system, and in response to sensing thesecond voltage deviation, activating the first contactor element to makecontact with a second tap in the first set of taps and the secondcontactor element to make contact with a second tap in the second set oftaps.

In certain aspects of the embodiment of the disclosure, the method canfurther include sensing each of the first voltage deviation and thesecond voltage deviation by using a motor electrically coupled to one ormore output terminals of the voltage regulator system, the motorcomprising a rotor shaft that rotates to a first angular position whenthe motor senses the first voltage deviation from the nominal outputvoltage and rotates to a second angular position when the motor sensesthe second voltage deviation from the nominal output voltage.

In certain aspects of the embodiment of the disclosure, the method canfurther pertain to each of the first tap changer and the second tapchanger having a circular plate having a central opening formechanically coupling, directly or indirectly, each of the first tapchanger and the second tap changer to the rotor shaft of the motor.

In certain aspects of the embodiment of the disclosure, the method canfurther pertain to the first voltage deviation from the nominal outputvoltage being a positive deviation from the nominal output voltage andthe second voltage deviation from the nominal output voltage being anegative deviation from the nominal output voltage.

In certain aspects of the embodiment of the disclosure, each of thepositive deviation and the negative deviation is defined on a percentagebasis with respect to the nominal output voltage.

In certain aspects of the embodiment of the disclosure, the method canfurther pertain to the split-coil transformer assembly including a firstreversing switch and a second reversing switch. The first reversingswitch is connected to the first coil winding and is operative toelectrically couple one of a first end or a second end of the first coilwinding to an output terminal of the voltage regulator system. Thesecond reversing switch, which is mechanically ganged with the firstreversing switch, is connected to the second coil winding, and operativeto electrically couple one of a first end or a second end of the secondcoil winding to the output terminal of the voltage regulator system whenthe first reversing switch electrically couples the one of a first endor the second end of the first coil winding to the output terminal ofthe voltage regulator system.

In one exemplary implementation in accordance with an embodiment of thedisclosure, a voltage regulator system can include a voltage regulationcontroller and a split-coil transformer assembly. The split-coiltransformer assembly can include a first coil winding, a first tapchanger, a first reversing switch, a second coil winding, a second tapchanger, and a second reversing switch. The first coil winding has afirst set of taps. The first tap changer includes a first contactorelement that is configured to make contact with one of the first set oftaps over a first period of time and another of the first set of tapsover a second period of time. The first reversing switch is connected tothe first coil winding and is operative to electrically couple one of afirst end or a second end of the first coil winding to an outputterminal of the voltage regulator system. The second coil winding, whichis electrically coupled in parallel with the first coil winding, has asecond set of taps. The second tap changer includes a second contactorelement that is mechanically ganged to the first contactor element ofthe first tap changer. The second contactor element is configured tomake contact with one of the second set of taps over the first period oftime and another of the second set of taps over the second period oftime. The second reversing switch is connected to the second coilwinding. The second reversing switch is mechanically ganged to the firstreversing switch and is operative to electrically couple one of a firstend or a second end of the second coil winding to the output terminal ofthe voltage regulator system when the first reversing switchelectrically couples the one of the first end or the second end of thefirst coil winding to the output terminal of the voltage regulatorsystem.

In certain aspects of the embodiment of the disclosure, the voltageregulator system can include a voltage sensing element for sensing anoutput voltage of the voltage regulator system. The voltage sensingelement is configured to provide a first positioning stimulus forplacing the first contactor element in contact with the one of the firstset of taps over the first period of time and a second positioningstimulus that is selected to place the first contactor element incontact with the another of the first set of taps over the second periodof time.

In certain aspects of the embodiment of the disclosure, the voltagesensing element can include a sense coil that is configured to detect anominal output voltage of the voltage regulator system.

In certain aspects of the embodiment of the disclosure, the sense coilcan include at least one of a primary winding or a secondary winding ofa motor. The motor includes a rotor shaft that rotates to a firstangular position when there is a first voltage deviation from thenominal output voltage and rotates to a second angular position whenthere is a second voltage deviation from the nominal output voltage.Furthermore, each of the first tap changer and the second tap changercan include a circular plate having a central opening for mechanicallycoupling, directly or indirectly, each of the first tap changer and thesecond tap changer to the rotor shaft of the motor.

In certain aspects of the embodiment of the disclosure, the firstvoltage deviation from the nominal output voltage is a positivedeviation from the nominal output voltage and the second voltagedeviation from the nominal output voltage is a negative deviation fromthe nominal output voltage.

In certain aspects of the embodiment of the disclosure, each of thepositive deviation and the negative deviation is defined on a percentagebasis with respect to the nominal output voltage.

Many modifications and other embodiments of the example descriptions setforth herein to which these descriptions pertain will come to mindhaving the benefit of the teachings presented in the foregoingdescriptions and the associated drawings. Thus, it will be appreciatedthe disclosure may be embodied in many forms and should not be limitedto the exemplary embodiments described above. Therefore, it is to beunderstood that the disclosure is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

That which is claimed is:
 1. A voltage regulator system comprising: a voltage regulation controller comprising a voltage sensing element; and a transformer assembly coupled to the voltage regulation controller, the transformer assembly comprising: a coil winding; a first multi-contact tap arrangement connected to the coil winding, the first multi-contact tap arrangement comprising a first set of contacts; a second multi-contact tap arrangement connected to the coil winding, the second multi-contact tap arrangement comprising a second set of contacts; and a multifurcated tap changer system, the multifurcated tap changer system comprising: a first tap changer comprising a first contactor element that makes contact with a first contact in the first set of contacts when the voltage regulation controller provides to the transformer assembly, a first positioning stimulus that is based at least in part on the voltage sensing element sensing a first voltage deviation from a nominal output voltage of the voltage regulator system, and makes contact with a first contact in the second set of contacts when the voltage sensing element senses a second voltage deviation from the nominal output voltage; and a second tap changer that is mechanically ganged to the first tap changer, the second tap changer comprising a second contactor element that is arranged to automatically make contact with a second contact in the first set of contacts when the voltage regulation controller provides to the transformer assembly, the first positioning stimulus, and to automatically make contact with a second contact in the second set of contacts when the first contactor element makes contact with the first contact in the second set of contacts.
 2. The voltage regulator system of claim 1, wherein the voltage sensing element comprises a motor electrically coupled to one or more output terminals of the voltage regulator system, the motor comprising a rotor shaft that rotates to a first angular position when the motor senses the first voltage deviation from the nominal output voltage and rotates to a second angular position when the motor senses the second voltage deviation from the nominal output voltage.
 3. The voltage regulator system of claim 2, wherein the multifurcated tap changer system includes at least one circular plate having a central opening that is provided for insertion of the rotor shaft of the motor.
 4. The voltage regulator system of claim 2, wherein the first voltage deviation from the nominal output voltage is either a positive or negative deviation from the nominal output voltage and the second voltage deviation from the nominal output voltage is either a negative or positive deviation from the nominal output voltage.
 5. The voltage regulator system of claim 1, wherein the transformer assembly further comprises: a reversing switch connected to the coil winding, the reversing switch operative to electrically couple one of a first end or a second end of the coil winding to an output terminal of the voltage regulator system.
 6. A method of regulating voltage using a voltage regulator system comprising: providing a voltage regulation controller comprising a voltage sensing element; providing a transformer assembly coupled to the voltage regulation controller, the transformer assembly comprising: a coil winding; a first multi-contact tap arrangement connected to the coil winding, the first multi-contact tap arrangement having a first set of contacts; a second multi-contact tap arrangement connected to the coil winding, the second multi-contact tap arrangement having a second set of contacts; and a multifurcated tap changer system, the multifurcated tap changer system comprising a first tap changer having a first contactor element and a second tap changer that is mechanically ganged to the first tap changer, the second tap changer having a second contactor element; sensing a first voltage deviation from a nominal output voltage of the voltage regulator system; in response to sensing the first voltage deviation, placing the first contactor element in contact with a first contact in the first set of contacts, the second contactor element automatically and concurrently making contact with a second contact in the first set of contacts; sensing a second voltage deviation from the nominal output voltage of the voltage regulator system; and in response to sensing the second voltage deviation, placing the first contactor element in contact with a first contact in the second set of contacts, the second contactor element automatically and concurrently making contact with a second contact in the second set of contacts.
 7. The method of claim 6, wherein sensing each of the first voltage deviation and the second voltage deviation comprises using a motor electrically coupled to one or more output terminals of the voltage regulator system, the motor comprising a rotor shaft that rotates to a first angular position when the motor senses the first voltage deviation from the nominal output voltage and rotates to a second angular position when the motor senses the second voltage deviation from the nominal output voltage.
 8. The method of claim 7, wherein the multifurcated tap changer system includes at least one circular plate having a central opening that is provided for insertion of the rotor shaft of the motor.
 9. The method of claim 6, wherein the first voltage deviation from the nominal output voltage is either a positive or negative deviation from the nominal output voltage and the second voltage deviation from the nominal output voltage is either a negative or positive deviation from the nominal output voltage.
 10. The method of claim 9, wherein each of the positive deviation and the negative deviation is defined on a percentage basis with respect to the nominal output voltage.
 11. The method of claim 6, wherein the transformer assembly further comprises: a reversing switch connected to the coil winding, the reversing switch operative to electrically couple one of a first end or a second end of the coil winding to an output terminal of the voltage regulator system.
 12. A voltage regulator system comprising: a transformer assembly comprising: a coil winding; a first multi-contact tap arrangement connected to the coil winding, the first multi-contact tap arrangement having a first set of contacts; a second multi-contact tap arrangement connected to the coil winding, the second multi-contact tap arrangement having a second set of contacts; a first tap changer comprising a first contactor element configured to make contact with a first contact of the first set of contacts over a first period of time and a first contact of the second set of contacts over a second period of time; a second tap changer comprising a second contactor element that is mechanically ganged to the first contactor element of the first tap changer, the second contactor element arranged to automatically make contact with a second contact of the first set of contacts over the first period of time and a second contact of the second set of contacts over the second period of time; and a reversing switch connected to the coil winding, the reversing switch operative to electrically couple one of a first end or a second end of the coil winding for presenting a reversal of winding sense to a load current that flows through the voltage regulator system and into a load when coupled to an output terminal of the voltage regulator system; and a voltage sensing element comprising a sense coil configured to detect a nominal output voltage of the voltage regulator system, the voltage sensing element configured to provide a first positioning stimulus for placing the first contactor element in contact with the first contact of the first set of contacts over the first period of time and a second positioning stimulus that is selected to concurrently place the first contactor element in contact with the second contact of the first set of contacts over the second period of time, the sense coil including at least a part of at least one of a primary winding or a secondary winding of a motor, the motor comprising a rotor shaft that rotates to a first angular position when there is a first voltage deviation from the nominal output voltage and rotates to a second angular position when there is a second voltage deviation from the nominal output voltage.
 13. The voltage regulator system of claim 12, wherein the first voltage deviation from the nominal output voltage is either a positive or negative deviation from the nominal output voltage and the second voltage deviation from the nominal output voltage is either a negative or positive deviation from the nominal output voltage.
 14. The voltage regulator system of claim 13, wherein each of the positive deviation and the negative deviation is defined on a percentage basis with respect to the nominal output voltage. 